ext4: fix xattr shifting when expanding inodes part 2

commit 418c12d08dc64a45107c467ec1ba29b5e69b0715 upstream.

When multiple xattrs need to be moved out of inode, we did not properly
recompute total size of xattr headers in the inode and the new header
position. Thus when moving the second and further xattr we asked
ext4_xattr_shift_entries() to move too much and from the wrong place,
resulting in possible xattr value corruption or general memory
corruption.

Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/fs/ext4/xattr.c b/fs/ext4/xattr.c
index 9ee6080f231ca6ec815fbef5e18a45409c971afc..2637e9b3b6ff6c9d5d0339a9616ba0d321306e38 100644 (file)
--- a/fs/ext4/xattr.c
+++ b/fs/ext4/xattr.c
@@ -1515,6 +1515,7 @@ retry:
                error = ext4_xattr_ibody_set(handle, inode, &i, is);
                if (error)
                        goto cleanup;
+               total_ino -= entry_size;
 
                entry = IFIRST(header);
                if (entry_size + EXT4_XATTR_SIZE(size) >= isize_diff)
@@ -1525,11 +1526,11 @@ retry:
                ext4_xattr_shift_entries(entry, -shift_bytes,
                        (void *)raw_inode + EXT4_GOOD_OLD_INODE_SIZE +
                        EXT4_I(inode)->i_extra_isize + shift_bytes,
-                       (void *)header, total_ino - entry_size,
-                       inode->i_sb->s_blocksize);
+                       (void *)header, total_ino, inode->i_sb->s_blocksize);
 
                isize_diff -= shift_bytes;
                EXT4_I(inode)->i_extra_isize += shift_bytes;
+               header = IHDR(inode, raw_inode);
 
                i.name = b_entry_name;
                i.value = buffer;